Friday 24 April 2020

REPAIR / SERVICING TV SHIVAKI STV-45LED18S

Technical description and composition of the TV SHIVAKI STV-45LED18S, type of panel and applicable modules. The composition of the modules.
SHIVAKI LED
Model: STV-45LED18S
Chassis / Version: JUC7.820.00169579
Panel: C450U17-E68-C (G11)
LED backlight: 45E6800 LB-C450U17-E68-C-G21-XRD1
T-CON: 9AVDJ1S52 IN8909A
LED driver (backlight): integrated into PSU
Power Supply (PSU): R-HS120D-1MF
MainBoard: JUC7.820.00169579 HLS71EJ-iU
IC MainBoard: CPU: MSD6586 (Mstar Dual Core), LM1117
Tuner: NoName
Control: WiFi: 131.G47603U-04
Technical Specifications STV-45LED18S
SHIVAKI STV-45LED18S
General repair guidelines for TV LCD LED
Possible malfunctions
- The SHIVAKI STV-45LED18S TV does not turn on, does not respond to the remote control and control panel buttons, indicators do not light up and do not blink.
Usually, with such manifestations, the defect is caused by faulty elements in the main power module R-HS120D-1MF. It is necessary to measure the output voltages in its secondary circuits, and if they are completely absent, it is necessary to check the serviceability of power switches and rectifier diodes for possible breakdown (short circuit).
In case of breakdowns in the secondary circuits, the converter can operate in a short circuit mode, and during a short circuit in the elements of the primary circuit, the mains fuse usually breaks.
Mos-Fet power switches, used in switching power supplies, sometimes fail due to a malfunction of any other elements that can put it out of operation in key mode or create an excess of the maximum permissible parameters of the switch. These can be elements supplying the PWM controller, frequency-setting or damping circuits, or negative feedback elements in the stabilization circuit. PWM controllers, in the absence of visible damage or frank short-circuit between the terminals, are checked by replacing with new, or obviously working.
- There is no image, there is sound, it is responding to the remote control. Or immediately after turning on for a second, the image may appear and immediately disappear.
A malfunction is usually most likely in these cases at the backlight nodes of the display matrix. The reason for this may be a break in the LED circuit, or a problem in stabilizing their power supply.
To check the LED strips, to open all the transitions of the LEDs, several tens of volts or more are needed, it is best to use a current source for such purposes. The breakage of several PN junctions connected in series cannot be detected with a multimeter or tester. In such cases, it is necessary to open the panel and check each LED. If your multimeter cannot open the LED transitions in forward bias, you can sometimes detect the presence of a PN junction of the protective zener diode by connecting the probes in the opposite direction. If the zener diode is broken or broken in short-circuit, then the LED is faulty and needs to be replaced.
- The TV does not turn on, does not respond to the remote control. The indicator blinks or signals standby mode.
Repair or diagnostics of the JUC7.820.00169579 motherboard should begin by checking the stabilizers and power converters needed to power the chips and matrix. If necessary, update or replace the software (software). Often, the MB (SSB) card must be replaced in case of complex malfunctions that are difficult to detect. When trying to repair, you should check its elements - CPU: MSD6586 (Mstar Dual Core) and replace failed chips with new ones. Some malfunctions may be due to the use of BGA soldering technologies in modern Main Board technologies. Typically, such defects are detected by local heating of the chip.
In cases where there is no tuning to the channels of on-air or cable television, you should make sure that the software is correct, as well as in accordance with the ratings of the supply voltage at the terminals of the NoName tuner. It is also necessary to check the presence of pulses of data exchange between the tuner and the processor via the I2C bus using an oscilloscope.
TV users and owners must remember that attempts to independently repair a SHIVAKI STV-45LED18S TV without the appropriate qualifications and the necessary experience can lead to serious negative consequences!

Repair MainBoard
The appearance of the MainBoard JUC7.820.00169579 is shown in the figure below:
JUC7.820.00169579
The appearance of the power supply
Main features of the SHIVAKI STV-45LED18S device:
Installed matrix (LED-panel) C450U17-E68-C (G11).
The matrix control uses the Timing Controller (T-CON) 9AVDJ1S52.
To power the backlight LEDs, a converter is used, combined with a power supply.
The formation of the necessary supply voltages for all nodes of the SHIVAKI STV-45LED18S TV is carried out by the power module R-HS120D-1MF, or its analogues.
MainBoard - the main board (motherboard) is a JUC7.820.00169579 module, using CPU chips: MSD6586 (Mstar Dual Core), LM1117 and others.
The NoName tuner provides television reception and channel tuning.


TV SHIVAKI STV-45LED18S with LCD C450U17-E68-C, diagonal size 45 "(114 cm) 16: 9 format. The required brightness of the screen 250 cd / m² is provided by LED backlight LED. Contrast, as the ratio of maximum brightness to minimum , it is 4000: 1. Direct LED backlighting with rear LEDs is realized in the LCD panel of the TV - Direct HD movies can be watched in the highest possible quality with a resolution of 3840x2160 pixels in the 4K UHD standard.
The STV-45LED18S TV has built-in SMART Software and a pre-installed Android Operating System. Connecting to the Internet can be done via Wi-Fi. Supported media file formats: MP3, MPEG4, HEVC (H.265), MKV, JPEG.
The power of the sound system 10 W (2x5 W) provide two speakers. It uses a NICAM stereo signal processing system and Sound Surround.
The external interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), AV, component, HDMI x3, USB x2, Ethernet (RJ-45), Wi-Fi. An output for connecting headphones is provided.
A digital tuner is capable of receiving television channels in the DVB-T MPEG4, DVB-C, DVB-T2 standards.
Overall dimensions: with stand 1017x643x204 mm, without stand 1017x583x89 mm.
TV Weight: with stand: 8.6 kg, without stand: 8.4 kg.
Attention! The C450U17-E68-C (G11) panel of the SHIVAKI STV-45LED18S LED TV is an expensive and unreliable element.
Avoid any impact on the glass and pressure on the surface of the screen to avoid damage to the LED panel!
It is also unsafe to get liquid on the screen. Sometimes one drop is enough if it flows down the glass onto the cables so that the TV becomes unrepairable.